The Screenshot of the Day is an eerie-looking scene from Gilneas with dry trees and vines or roots coming out of the ground. At the center is a very ancient and dried tree that has grown below an Elven ruins. Parts of the structure are merged in different places with the giant tree.
A very curious scene because there is no lore about an elven presence in Gilneas prior to the foundation of Gilneas, unless Gilneas, and Silverpine Forest were part of Tirisfal Glades (the way Blasted Lands and Swamp of Sorrows was once Black Morass).
Hopefully some Worgen quests can shine some light about this mysterious location. Zooming in into the screenshot, it looks like the bottom of the giant tree is hollow like Grizzlemaw. There is a brilliant pyre within.